It was a World Cup debut to forget for Manchester United goalkeeper Senne Lammens, whose mistake proved costly for Belgium as Spain advanced to the semi-finals, driven once again by the ever-reliable Mikel Merino.

Lammens had to step in unexpectedly against Spain and will face intense scrutiny for failing to hold onto a long-range effort from Pau Cubarsi. It was a cruel twist of fate for the 22-year-old, who had barely featured before this moment.

Belgium had initially relied on La Liga’s top shot-stopper, Thibaut Courtois, to keep Spain at bay. However, Courtois’ evening came to an abrupt end after 70 minutes when injury forced him off the pitch.

Lammens entered as his replacement, making his first appearance of the tournament. For about 15 minutes, Spain struggled to find any clear openings, but the deadlock was eventually broken when the substitute goalkeeper’s error proved decisive.

When Lammens spilled Cubarsi’s drive, Merino—who had only just been introduced—was quickest to react, slotting home to give Spain the lead they needed.

Merino once again demonstrated his knack for scoring crucial goals, reminding Spain of the attacking spark they had been missing prior to his introduction.

Spain, however, had not found this quarter-final as straightforward as expected, even after taking an early lead within the first half-hour. A slick exchange between Pedro Porro and Lamine Yamal on the right flank ended with a cut-back to Dani Olmo, whose shot was parried by Courtois.

Although Courtois made the initial save, he couldn’t hold onto the ball, and Fabian Ruiz reacted quickest to smash in the rebound and put Spain ahead.

Spain began to find their rhythm, moving the ball around fluently and involving Yamal more frequently, but their advantage was short-lived. Roughly 10 minutes later, Charles De Ketelaere rose highest to head in Belgium’s equaliser, marking the first time Spain had conceded in this World Cup.

Belgium had a brief moment of hope in the second half when the ball appeared to strike Rodri’s arm inside the penalty area, but their appeals were waved away by the referee.

The game’s momentum shifted again when Courtois, who had earlier received treatment during a hydration break, was forced off with 20 minutes to go. His absence left a massive void, one Lammens was tasked with filling under immense pressure.

Lammens, who had been an understated but dependable figure for his club last season, found the situation overwhelming. The young goalkeeper will likely replay that moment in his mind for a long time—his mistake leading to Spain’s decisive goal.

It is worth noting that Courtois himself had spilled the ball for Spain’s first goal, but Lammens’ error was far more glaring and will be remembered as the defining moment of Belgium’s World Cup exit.

For Lammens, there will be little comfort in knowing even Courtois faltered. His error will come to symbolise Belgium’s elimination and the fading light of their once-celebrated golden generation.

He must now move forward, determined not to let this setback overshadow what has been a promising beginning to his Premier League career. With Courtois likely to have played his final World Cup, Lammens is seen as his natural heir—though he will have more time to prepare for that role next time.

For the moment, however, he must come to terms with being the unfortunate face of Belgium’s departure from the tournament.

Still, the result was not entirely unexpected. Spain entered the match as favourites and will now pose a major challenge to France, the leading contenders for the title.

With a big-game player like Merino in their ranks, Spain once again proved that having clutch performers makes all the difference at this level.

Ultimately, this match will be remembered as one defined by two substitutes—one who rose to the occasion, and another who will wish he could forget his introduction altogether.